Semiconductor devices are manufactured by increasingly complex process steps and with increasingly dense element integration. Thus, in semiconductor device manufacturing, high processing controllability is required not only in the lateral direction but also in the vertical direction. The amount of polishing by chemical mechanical polishing (CMP) tend to increase as the steps or undulations in the device structure become greater with increased complexity of the process steps and as more and more layers are stacked with increased element density.
The condition or the state of the polish pad used in CMP changes over repetitive use by wear, deformation, etc. The change in the condition or the state of the polish pad increases with polish amount and thus, has greater influence on polish performance as the polish pad is used more heavily. The change in the state of the polish pad may destabilize the polish properties and may cause variations in the polish results.